6973308: Missing zero length check before repne scas in check_klass_subtype_slow_path()

Summary: set Z = 0 (not equal) before repne_scan() to indicate that class was not found when RCX == 0.
Reviewed-by: never, phh

src/cpu/x86/vm/assembler_x86.cpp

@@ -7568,21 +7568,27 @@ void MacroAssembler::check_klass_subtype_slow_path(Register sub_klass,
 
   // Scan RCX words at [RDI] for an occurrence of RAX.
   // Set NZ/Z based on last compare.
+  // Z flag value will not be set by 'repne' if RCX == 0 since 'repne' does
+  // not change flags (only scas instruction which is repeated sets flags).
+  // Set Z = 0 (not equal) before 'repne' to indicate that class was not found.
 #ifdef _LP64
   // This part is tricky, as values in supers array could be 32 or 64 bit wide
   // and we store values in objArrays always encoded, thus we need to encode
   // the value of rax before repne.  Note that rax is dead after the repne.
   if (UseCompressedOops) {
-    encode_heap_oop_not_null(rax);
+    encode_heap_oop_not_null(rax); // Changes flags.
     // The superclass is never null; it would be a basic system error if a null
     // pointer were to sneak in here.  Note that we have already loaded the
     // Klass::super_check_offset from the super_klass in the fast path,
     // so if there is a null in that register, we are already in the afterlife.
+    testl(rax,rax); // Set Z = 0
     repne_scanl();
   } else
 #endif // _LP64
+  {
+    testptr(rax,rax); // Set Z = 0
     repne_scan();
-
+  }
   // Unspill the temp. registers:
   if (pushed_rdi)  pop(rdi);
   if (pushed_rcx)  pop(rcx);
@@ -8257,30 +8263,35 @@ void MacroAssembler::store_heap_oop_null(Address dst) {
   }
 }
 
-// Algorithm must match oop.inline.hpp encode_heap_oop.
-void MacroAssembler::encode_heap_oop(Register r) {
+#ifdef ASSERT
+void MacroAssembler::verify_heapbase(const char* msg) {
   assert (UseCompressedOops, "should be compressed");
   assert (Universe::heap() != NULL, "java heap should be initialized");
-  if (Universe::narrow_oop_base() == NULL) {
-    verify_oop(r, "broken oop in encode_heap_oop");
-    if (Universe::narrow_oop_shift() != 0) {
-      assert (LogMinObjAlignmentInBytes == Universe::narrow_oop_shift(), "decode alg wrong");
-      shrq(r, LogMinObjAlignmentInBytes);
-    }
-    return;
-  }
-#ifdef ASSERT
   if (CheckCompressedOops) {
     Label ok;
     push(rscratch1); // cmpptr trashes rscratch1
     cmpptr(r12_heapbase, ExternalAddress((address)Universe::narrow_oop_base_addr()));
     jcc(Assembler::equal, ok);
-    stop("MacroAssembler::encode_heap_oop: heap base corrupted?");
+    stop(msg);
     bind(ok);
     pop(rscratch1);
   }
+}
+#endif
+
+// Algorithm must match oop.inline.hpp encode_heap_oop.
+void MacroAssembler::encode_heap_oop(Register r) {
+#ifdef ASSERT
+  verify_heapbase("MacroAssembler::encode_heap_oop: heap base corrupted?");
 #endif
   verify_oop(r, "broken oop in encode_heap_oop");
+  if (Universe::narrow_oop_base() == NULL) {
+    if (Universe::narrow_oop_shift() != 0) {
+      assert (LogMinObjAlignmentInBytes == Universe::narrow_oop_shift(), "decode alg wrong");
+      shrq(r, LogMinObjAlignmentInBytes);
+    }
+    return;
+  }
   testq(r, r);
   cmovq(Assembler::equal, r, r12_heapbase);
   subq(r, r12_heapbase);
@@ -8288,9 +8299,8 @@ void MacroAssembler::encode_heap_oop(Register r) {
 }
 
 void MacroAssembler::encode_heap_oop_not_null(Register r) {
-  assert (UseCompressedOops, "should be compressed");
-  assert (Universe::heap() != NULL, "java heap should be initialized");
 #ifdef ASSERT
+  verify_heapbase("MacroAssembler::encode_heap_oop_not_null: heap base corrupted?");
   if (CheckCompressedOops) {
     Label ok;
     testq(r, r);
@@ -8310,9 +8320,8 @@ void MacroAssembler::encode_heap_oop_not_null(Register r) {
 }
 
 void MacroAssembler::encode_heap_oop_not_null(Register dst, Register src) {
-  assert (UseCompressedOops, "should be compressed");
-  assert (Universe::heap() != NULL, "java heap should be initialized");
 #ifdef ASSERT
+  verify_heapbase("MacroAssembler::encode_heap_oop_not_null2: heap base corrupted?");
   if (CheckCompressedOops) {
     Label ok;
     testq(src, src);
@@ -8335,40 +8344,21 @@ void MacroAssembler::encode_heap_oop_not_null(Register dst, Register src) {
 }
 
 void  MacroAssembler::decode_heap_oop(Register r) {
-  assert (UseCompressedOops, "should be compressed");
-  assert (Universe::heap() != NULL, "java heap should be initialized");
+#ifdef ASSERT
+  verify_heapbase("MacroAssembler::decode_heap_oop: heap base corrupted?");
+#endif
   if (Universe::narrow_oop_base() == NULL) {
     if (Universe::narrow_oop_shift() != 0) {
       assert (LogMinObjAlignmentInBytes == Universe::narrow_oop_shift(), "decode alg wrong");
       shlq(r, LogMinObjAlignmentInBytes);
     }
-    verify_oop(r, "broken oop in decode_heap_oop");
-    return;
-  }
-#ifdef ASSERT
-  if (CheckCompressedOops) {
-    Label ok;
-    push(rscratch1);
-    cmpptr(r12_heapbase,
-           ExternalAddress((address)Universe::narrow_oop_base_addr()));
-    jcc(Assembler::equal, ok);
-    stop("MacroAssembler::decode_heap_oop: heap base corrupted?");
-    bind(ok);
-    pop(rscratch1);
+  } else {
+    Label done;
+    shlq(r, LogMinObjAlignmentInBytes);
+    jccb(Assembler::equal, done);
+    addq(r, r12_heapbase);
+    bind(done);
   }
-#endif
-
-  Label done;
-  shlq(r, LogMinObjAlignmentInBytes);
-  jccb(Assembler::equal, done);
-  addq(r, r12_heapbase);
-#if 0
-   // alternate decoding probably a wash.
-   testq(r, r);
-   jccb(Assembler::equal, done);
-   leaq(r, Address(r12_heapbase, r, Address::times_8, 0));
-#endif
-  bind(done);
   verify_oop(r, "broken oop in decode_heap_oop");
 }
 
@@ -8410,9 +8400,11 @@ void  MacroAssembler::decode_heap_oop_not_null(Register dst, Register src) {
         addq(dst, r12_heapbase);
       }
     }
-  } else if (dst != src) {
+  } else {
     assert (Universe::narrow_oop_base() == NULL, "sanity");
-    movq(dst, src);
+    if (dst != src) {
+      movq(dst, src);
+    }
   }
 }
 

src/cpu/x86/vm/assembler_x86.hpp

@@ -1714,6 +1714,9 @@ class MacroAssembler: public Assembler {
 
   // if heap base register is used - reinit it with the correct value
   void reinit_heapbase();
+
+  DEBUG_ONLY(void verify_heapbase(const char* msg);)
+
 #endif // _LP64
 
   // Int division/remainder for Java

src/share/vm/runtime/globals.hpp

@@ -2442,6 +2442,10 @@ class CommandLineFlags {
           "Call fatal if this exception is thrown.  Example: "              \
           "java -XX:AbortVMOnException=java.lang.NullPointerException Foo") \
                                                                             \
+  notproduct(ccstr, AbortVMOnExceptionMessage, NULL,                        \
+          "Call fatal if the exception pointed by AbortVMOnException "      \
+          "has this message.")                                              \
+                                                                            \
   develop(bool, DebugVtables, false,                                        \
           "add debugging code to vtable dispatch")                          \
                                                                             \

src/share/vm/utilities/exceptions.cpp

@@ -117,7 +117,7 @@ void Exceptions::_throw(Thread* thread, const char* file, int line, Handle h_exc
                   (address)h_exception(), file, line, thread);
   }
   // for AbortVMOnException flag
-  NOT_PRODUCT(Exceptions::debug_check_abort(h_exception));
+  NOT_PRODUCT(Exceptions::debug_check_abort(h_exception, message));
 
   // Check for special boot-strapping/vm-thread handling
   if (special_exception(thread, file, line, h_exception)) return;
@@ -375,17 +375,26 @@ ExceptionMark::~ExceptionMark() {
 
 #ifndef PRODUCT
 // caller frees value_string if necessary
-void Exceptions::debug_check_abort(const char *value_string) {
+void Exceptions::debug_check_abort(const char *value_string, const char* message) {
   if (AbortVMOnException != NULL && value_string != NULL &&
       strstr(value_string, AbortVMOnException)) {
-    fatal(err_msg("Saw %s, aborting", value_string));
+    if (AbortVMOnExceptionMessage == NULL || message == NULL ||
+        strcmp(message, AbortVMOnExceptionMessage) == 0) {
+      fatal(err_msg("Saw %s, aborting", value_string));
+    }
   }
 }
 
-void Exceptions::debug_check_abort(Handle exception) {
+void Exceptions::debug_check_abort(Handle exception, const char* message) {
   if (AbortVMOnException != NULL) {
     ResourceMark rm;
-    debug_check_abort(instanceKlass::cast(exception()->klass())->external_name());
+    if (message == NULL && exception->is_a(SystemDictionary::Throwable_klass())) {
+      oop msg = java_lang_Throwable::message(exception);
+      if (msg != NULL) {
+        message = java_lang_String::as_utf8_string(msg);
+      }
+    }
+    debug_check_abort(instanceKlass::cast(exception()->klass())->external_name(), message);
   }
 }
 #endif

src/share/vm/utilities/exceptions.hpp

@@ -143,8 +143,8 @@ class Exceptions {
   static void throw_stack_overflow_exception(Thread* thread, const char* file, int line);
 
   // for AbortVMOnException flag
-  NOT_PRODUCT(static void debug_check_abort(Handle exception);)
-  NOT_PRODUCT(static void debug_check_abort(const char *value_string);)
+  NOT_PRODUCT(static void debug_check_abort(Handle exception, const char* message = NULL);)
+  NOT_PRODUCT(static void debug_check_abort(const char *value_string, const char* message = NULL);)
 };
 
 

src/share/vm/utilities/vmError.cpp

@@ -479,8 +479,8 @@ void VMError::report(outputStream* st) {
 
        if (fr.sp()) {
          st->print(",  sp=" PTR_FORMAT, fr.sp());
-         st->print(",  free space=%" INTPTR_FORMAT "k",
-                     ((intptr_t)fr.sp() - (intptr_t)stack_bottom) >> 10);
+         size_t free_stack_size = pointer_delta(fr.sp(), stack_bottom, 1024);
+         st->print(",  free space=" SIZE_FORMAT "k", free_stack_size);
        }
 
        st->cr();